Mucin-like carcinoma-associated antigen (mca) serum levels in breast-cancer - a critical-appraisal.

MCA serum levels were determined in 196 patients with benign breast disease (BD) and in 371 patients with breast cancer. MCA values were abnormal in 30.6% of the patients with BD. In breast cancer patients, significant increases were only found in metastatic disease (89.1%). MCA levels were not correlated with tumor size; on the contrary, the tumor marker showed a strict relation to axillary lymph node involvement. Moreover, the location of metastases and the number of sites involved seem to increase MCA concentrations. The MCA antigen seems to be a promising tool only for monitoring patients with advanced breast cancer.